Revert "Disable flaky test lib.libc.sys.setrlimit_test.setrlimit_stack"

The stack gap implementation is disabled by default now, so the test
passes.

This reverts commit dad71022.

PR:		259969
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation

contrib/netbsd-tests/lib/libc/sys/t_setrlimit.c

@@ -550,9 +550,6 @@ ATF_TC_BODY(setrlimit_stack, tc)
 {
 	struct rlimit res;
 
-	if (atf_tc_get_config_var_as_bool_wd(tc, "ci", false))
-		atf_tc_skip("https://bugs.freebsd.org/259969");
-
 	/* Ensure soft limit is not bigger than hard limit */
 	res.rlim_cur = res.rlim_max = 4192256;
 	ATF_REQUIRE(setrlimit(RLIMIT_STACK, &res) == 0);